Evolution of Blast Furnace Iron Making Jan10

Evolution of Blast Furnace Iron Making...

Evolution of Blast Furnace Iron Making The origin of the first smelting of iron is concealed in the unrecorded history of human civilization. The first evidence of iron implements being used in ancient times actually comes from Egypt where an iron tool was found in a joint between two stones in a pyramid. The origin of many prehistoric iron implements was probably meteoric iron. Meteoric iron contains 5 % to 26 % nickel (Ni) while smelted iron contains only traces of Ni and hence iron artifacts made from meteors can be differentiated from objects of smelted iron. More than 4,000 years ago, people discovered meteoric iron. But it was another 2,000 years before the production of iron from mined iron ore began. The earliest finds of smelted iron in India date back to 1800 BCE (Before Common Era).  The smelting of iron is said to have taken place among the Calybes of Armenia, subjects of the Hittite Empire, at about 1500 BCE. When their empire collapsed around 1200 BCE, the various tribes took the knowledge of iron making with them, spreading it across Europe and Asia. The knowledge of ironworking in all of Europe and Western Asia is ultimately traced to this source. The Iron Age began with the discovery of smelting of iron. Beginning of iron smelting As with the reduction of cop­per sulfide ores, the first reduction of iron oxide was probably accidental. It was the powers of observation that led these ancient metallurgists (who were the miners, chemists, and technologists of their day) to realize that iron could be produced in simple furnaces by direct carbon (C) reduction of the oxide ore. The first recorded depiction of a smelting process was found on the wall of an Egyptian tomb dating to...

Selection of Coal for inclusion in Coal Blend in Coke Making Sep26

Selection of Coal for inclusion in Coal Blend in Coke Making...

Selection of Coal for inclusion in Coal Blend in Coke Making Blending of coals is necessary from economical point of view by reducing the percentage of high cost, prime or hard coking coals and replacing it with medium or soft coking coals. In some coke oven plants even a small percentage of non-coking or steam coals have also been used in the blend. Selection of a proper coal blend for use in by product coke ovens is always a big challenge for the coke producer since the blend has to meet the following requirements. It is to meet the requirement of crushing during coal preparation. All the components of the coals are neither be over crushed or under crushed. The sized coal blend for charging the coke ovens is to meet the requirements of density, flow, and the size fractions. It is to have necessary coking and caking properties for producing coke of quality which meets the quality requirements of blast furnace (BF) coke. The three basic quality requirements of BF coke are (i) to provide heat for the endothermic reactions taking place in the blast furnace, (ii) to act as a reducing agent by producing the necessary reduction gases, and (iii) to provide a permeable support in the BF for the iron bearing burden. It is to provide safe pushing performance in coke ovens. It must not put excessive pressure on coke oven walls during the process of coking and damage them. It should meet the yield requirements not only of BF coke but also of coke oven gas. A proper coal blend will not produce excessive nut coke and coke breeze. It is to be economical. In view of the above varied types of requirements, the decisions regarding coal blends are not...

Types of Energy used in a Steel Plants and Energy Conservation...

Types of Energy used in a Steel Plants and Energy Conservation Energy is needed to do any work. Energy can be in the form of potential energy or it can be in the form kinetic energy. Potential energy is stored energy and for doing the work it is to be released from the storage.  Common example of potential energy are fuel energy, chemical energy and  pressure energy etc. Kinetic energy is energy due to motion and example of kinetic energy is electric energy which is the movement of electrons. Energy conservation activities are the efforts made towards reduction in energy consumption for doing a work. These efforts can be in the form of reduction of energy wastages, recovery and recycling of waste energy, and/or by improving the energy efficiency of the processes. Various forms of energy used in an integrated steel plant are described below.  Fuel energy Fuel energy is the potential energy which constitutes the major component of all the form of energies used in the steel plant. Fuel energy is used in the form of primary fuels and the byproduct fuels. Primary fuels used in steel plant are (i) solid fuels, (ii) liquid fuels, and (iii) gaseous fuels. Byproduct fuels are mainly coke oven gas recovered during coking process of metallurgical coals, blast furnace gas recovered from blast furnace during the production of hot metal, converter gas recovered during the production of steel in the basic oxygen furnace process, and coal tar fuel produced during the cleaning of the raw coke oven gas produced while coking of the metallurgical coals. Solid fuels used in the steel plant are coal and/or coke. Solid fuels constitute the highest percentage of energy consumed in steel plant. Both metallurgical (coking) coals and non coking coals are...

Understanding Coke Making in Byproduct Coke Oven Battery Mar09

Understanding Coke Making in Byproduct Coke Oven Battery...

Understanding Coke Making in Byproduct Coke Oven Battery  Coke is one of the basic materials used in blast furnaces for the conversion of iron ore into hot metal (liquid iron), most of which is subsequently processed into steel. The major portion of coke produced is used for the production of hot metal. Coke is also used by a number of other industries, namely iron foundries, nonferrous smelters, and chemical plants. It is also used in steel making as a carburizing material. Coke and coke by-products, including coke oven gas, are produced by the pyrolysis (heating in the absence of air) of suitable grades of coal. The process also includes the processing of coke oven gas to remove tar,  ammonia (usually recovered as ammonium sulphate), phenol, naphthalene, light oil, and sulphl, and sulfs under links n of coal)  period.e doorg nitrogen gas is used for the production of steam and then power.ur before the gas is used as fuel for heating the ovens. The coke making industry consists of two sectors, integrated plants and merchant plants. Integrated plants are owned by or affiliated with iron-and steel producing plants who produce blast furnace coke primarily for consumption in their own blast furnaces. Independent merchant plants produce furnace and/or foundry coke for sale in the open market. These plants sell most of their products to other plants engaged in blast furnace, foundry, and nonferrous smelting operations. A good quality coke is generally made from carbonization of good quality coking coal. Coking coals are defined as those coals that on carbonization pass through softening, swelling, and re-solidification to coke. One important consideration in selecting a coal blend is that it should not exert a high coke oven wall pressure and should contract sufficiently to allow the coke to...

Coke Oven Gas Injection in a Blast Furnace Jul19

Coke Oven Gas Injection in a Blast Furnace...

Coke Oven Gas Injection in a Blast Furnace  The iron and steel industry is one of the main consumer of energy and hence responsible for high emissions of carbon di oxide (CO2). Despite remarkable decrease in specific CO2 emissions by most of the steel plants, the total amount of CO2 emissions is growing across worldwide due to the continuous increasing of steel production which has reached to a level of 1606 million tons in 2013. Nowadays the steel industry is facing an increasing demand to minimize the energy consumption and gas emissions especially from ironmaking processes. The efficient use of byproduct gases is essentially important for the profitability of steel plant operation due to the high energy volumes and the costs involved. The injection of coke oven gas (COG) into the modern blast furnace is one of effective measures for steel industry to achieve low carbon ironmaking, energy saving and emission reduction. Coke is an essential input to the iron making process and is produced by heating coal in coke ovens. To make coke, coal is heated in the absence of oxygen to drive volatile matter from it. COG is produced as a byproduct of the process in case of byproduct coke oven batteries normally installed in steel plants. The specific amount of COG generated during coke making in the byproduct coke ovens is in the range from 290 to 340 N cum/t of coal charge depending on the volatile matters in the coal charge. The COG is currently used after its cleaning from tar, naphthalene, raw benzene, ammonia, and sulfur for heating of blast furnace stoves, ignition furnaces in sintering plant, heating furnace in rolling mills and electric power generation in power plant. The COG has a composition which consists of around 55...